I have a 2000 150 HPDI which I purchased new in 2001 and I have about 250 hours on the engine with many of those hours at low RPM while trolling. I've used nothing but premium oil and I frequently use Ring Free. After a period of trolling I run the engine at speed for about half an hour before trailering. My dealer about freaked when he saw how many hours the engine was used below 1000 RPM and said I was damaging the engine. I posed the question of possible engine damage to a Yamaha rep several years ago and he stated the engine would not be harmed in any way as long as I frequently ran the engine at higher RPM to run the "crud" out of it. I pose this question to the experienced Yamaha owners and tech's to get your feedback. Thanks.
P.S. the engine performs perfectly and I hate to get a trolling motor because the big engine trolls at the perfect speed for the fishng I do.
P.S. the engine performs perfectly and I hate to get a trolling motor because the big engine trolls at the perfect speed for the fishng I do.